From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754736AbbHBAcn (ORCPT ); Sat, 1 Aug 2015 20:32:43 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36695 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753982AbbHBAaP (ORCPT ); Sat, 1 Aug 2015 20:30:15 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Or Gerlitz" , "Jack Morgenstein" , "Haggai Eran" , "Shachar Raindel" , "Yann Droneaud" , "Doug Ledford" , "Sagi Grimberg" Date: Sun, 02 Aug 2015 01:02:37 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 044/164] IB/core: don't disallow registering region starting at 0x0 In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.249 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.70-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Yann Droneaud commit 66578b0b2f69659f00b6169e6fe7377c4b100d18 upstream. In a call to ib_umem_get(), if address is 0x0 and size is already page aligned, check added in commit 8494057ab5e4 ("IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic") will refuse to register a memory region that could otherwise be valid (provided vm.mmap_min_addr sysctl and mmap_low_allowed SELinux knobs allow userspace to map something at address 0x0). This patch allows back such registration: ib_umem_get() should probably don't care of the base address provided it can be pinned with get_user_pages(). There's two possible overflows, in (addr + size) and in PAGE_ALIGN(addr + size), this patch keep ensuring none of them happen while allowing to pin memory at address 0x0. Anyway, the case of size equal 0 is no more (partially) handled as 0-length memory region are disallowed by an earlier check. Link: http://mid.gmane.org/cover.1428929103.git.ydroneaud@opteya.com Cc: Shachar Raindel Cc: Jack Morgenstein Cc: Or Gerlitz Signed-off-by: Yann Droneaud Reviewed-by: Sagi Grimberg Reviewed-by: Haggai Eran Signed-off-by: Doug Ledford Signed-off-by: Ben Hutchings --- drivers/infiniband/core/umem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -101,8 +101,8 @@ struct ib_umem *ib_umem_get(struct ib_uc * If the combination of the addr and size requested for this memory * region causes an integer overflow, return error. */ - if ((PAGE_ALIGN(addr + size) <= size) || - (PAGE_ALIGN(addr + size) <= addr)) + if (((addr + size) < addr) || + PAGE_ALIGN(addr + size) < (addr + size)) return ERR_PTR(-EINVAL); if (!can_do_mlock())